Wheel alignment measuring apparatus

ABSTRACT

A wheel alignment measuring apparatus for determining vehicle wheel camber and toe characteristics. A pair of telescopic measuring heads in the form of tubes are adjustable to the lateral spacing of a pair of vehicle wheels. Each tubular head is provided with an axial rod projecting through the head and carrying an elongated member having spaced probes engagable with diametrically opposed points on the rim of the wheel hub. The elongated member swings to an inclined position corresponding to the inclination of the wheel relative to a true reference plane causing movement of the rod, the rear end of which serves as a pointer associated with a calibrated scale to indicate the degree of wheel inclination.

United States Patent [191 Cufrini WHEEL ALIGNMENT MEASURING APPARATUS[75] Inventor:

[73] Assignee: Allitalia Import-Export Inc.,

Buffalo, NY.

Franco Cufrini, Frosinone, Italy [22] Filed: July 21, 1972 [21] Appl.No.: 273,787

[521 U.S. Cl. 33/203.17, 33/203.15 [51] Int.- Cl. G01b 5/255 [58] Fieldof Search ..33/203, 203.12, 203.15,

[ 56] References Cited Feb. 26, 1974 7/1940 Norway 33/203 9/1964 GreatBritain 33/203.l7

[5 7] ABSTRACT A wheel alignment measuring apparatus for determiningvehicle wheel camber and toe characteristics. A pair of telescopicmeasuring heads in the form of tubes are adjustable to the lateralspacing of a pair of vehicle wheels. Each tubular head is provided withan axial rod projecting through the head and carrying an elongatedmember having spaced probes engagable with diametrically opposed pointson the rim of the wheel hub. The elongated member swings to an inclinedposition corresponding to the inclination of the wheel relative to atrue reference plane causing movement of the rod, the rear end of whichserves as a pointer associated with a calibrated scale to indicate thedegree of wheel inclination."

7 Claims, 9 Drawing Figures BACKGROUND OF THE INVENTION This inventionrelates to a measuring apparatus and, more particularly, to a measuringapparatus for determining the true alignment of vehicle wheels.

Numerous devices have been developed for the purpose of measuringvehicle wheel alignment. Many of these devices are extremelycomplicated, incorporating electronic detectors and sophisticatedequipment, requiring a large amount of space and the services of anappropriately trained and skilled technician. Generally, these elaboratemeasuring apparatus are not practical for use in the smaller garages orservice stations. Other mechanical measuring devices are known, whichare complex and cumbersome in construction, difficult and time consumingto set up, and which are generally adapted for one type of measuringonly, such as the toe characteristics of the vehicle wheels for example.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of thepresent invention to provide a novel and simple wheel alignmentmeasuring apparatus for determining both vehicle wheel toe and cambercharacteristics with great accuracy and which can be readily used byuntrained personnel possessing relatively little skill.

Another object of this invention is to provide a wheel measuring devicewhich is simple and strong in construction, relatively low in costsrendering it practical for small garages and service stations, ruggedand durable in use, and highly accurate in operation.

The wheel alignment measuring apparatus of this invention ischaracterized by the provision of a pair of telescopic measuring headsin the form of tubes adjustable to the lateral spacing of a pair ofvehicle wheels, the tubular heads being provided with means centeringthe heads relative to the wheel hub axes. A transversely extending,elongated member is mounted on the projecting end of a rod passingthrough each tubular head and is provided with spaced probes, radiallyequidistant from the hub axis and engagable with diametrically opposedpoints on the rim of each wheel. hub. Tilting movement of the elongatedmember, due to the inclination of a wheel, is transmitted to the rod,which has a pointer at the rear end thereof operatively associated witha scale for indicating the degree of camber and the toe characteristicsof the wheel.

The foregoing and other objects, advantages and characterizing featuresof the present invention will become clearly apparent from the ensuingdetailed description of an illustrative embodiment thereof, takentogether with the accompanying drawings wherein like reference numeralsdenote like parts throughout the various views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view ofthe wheel alignment measuring apparatus of this invention, shown inoperative position relative to the front wheels of a vehicle;

FIG. 2 is a plan view thereof;

FIG. 3 is a side perspective view of one of the measuring tubular headsof this invention;

FIG. 4 is a fragmentary perspective view, illustrating the mode ofcentering the measuring apparatus of this invention relative to a wheelto be measured;

FIG. 5 is a rear end view of the measuring head and certain sensingelements incorporated in the measuring apparatus of this invention;

FIG. 6 is a front end view of the apparatus of FIG. 5;

FIG. 7 is a plan view, partly in section, of the apparatus of FIG. 5;

FIG. 8 is a sectional view, on an enlarged scale, taken about on line8-8 of FIG. 7, and showing the front face of the measuring head of thisinvention; and

FIG. 9 is a fragmentary, longitudinal sectional view, on an enlargedscale, .of the front portion of the measuring head of FIG. 7.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT Referring now indetail to the illustrative embodiment depicted in the accompanyingdrawings, there is shown in FIG. 1 a wheel alignment measuringapparatus, generally designated 10 and constructed in accordance withthis invention, shown positioned adjacent the front end of a vehicle Vfor measuring the camber and toe characteristics of the wheels Wthereof. Apparatus 10 comprises a frame 12 having an elongated tubularmember 14 adapted to extend transversely of the vehicle V. A pair ofcrossbars 16 are releasably secured to the opposite ends of member 14,each cross bar 16 being provided with a generally circular extension 18secured to the end of member 14 by a suitable fastener 20. Each crossbar16 is provided with downwardly curved end portions 22 serving assupports adapted to rest on the floor or any other suitable supportingsurface.

A pair of angularly bent arms 24 are mounted on tubular member 14 forsliding movement relative thereto. Each arm 24 consists of a pair ofangularly related tubular portions 26 and 28, the former terminating ina sleeve or collar 30 slidably mounted on tubular member 14. A set screw32 is mounted in collar 30 for securing the same in a selected positionon tubular member 14. A sleeve 34 is welded or otherwise fixedly securedto the end of tubular portion 28 for receiving a tubular measuring head36 therethrough. A set screw 37 is mounted in sleeve 34 for securinghead 36 in the selected position relative to sleeve 34. Since arms 24and heads 36 employed-at. the opposite ends of tubular member 14 areidentical in construction, it is believed that a detailed description ofonly one will suffice, it being understood that the same referencecharacters identify similar parts.

As shown in FIG. 7, head 36 comprises an elongated cylindrical body ofshell 38 having a front end wall 40 welded or otherwise fixedly securedto shell 38. A central opening 42 is provided in front end wall 40 forreceiving a rod 44 therethrough, the opening 42 being somewhat largerthan rod 44 to permit lateral play thereof. Rod 44 has a threadedportion 46 extending through opening 42 and terminating in a projectingstud 48 of reduced diameter and a major reduced diameter portion 50terminating in a pointer 52'.

The rear end of shell 38 is closed by a cap having a slot 62 therein forreceiving the distal end of pointer 52. A calibrated scale 64,comprising a series of markings imprinted or impressed on the outersurface of cap 60 on opposite sides of slot 62, indicates measurementsin millimeters, or degrees, as desired.

A circular plate 66 is secured to the outer face of front end wall 40 byscrew fasteners 68 extending through suitable openings in plate 66 andthreaded into tapped openings provided in front end wall 40. A generallyrectangularly shaped central opening 70 having rounded ends is providedin circular plate 66 for partially receiving a key 72 having acomplementaryshaped outline therein. Key 72 has a central opening 74 forreceiving the forward end of rod 44 therethrough with a snug fit.

Also mounted on the forward end of rod 44 is an elongated channel member76 extending in a direction normal to rod 44. Channel member 76 isprovided with a central opening receiving rod 44 and clamped on theforward end of rod threaded portion 46 between a pair of nuts 78. Theaxial outer end of key 72 is fitted within a shallow groove 80 formed inchannel member 76. As shown in FIGS. 7 and 8, key 72 serves to orientchannel member 76 in the proper direction, parallel to slot 62, and alsoserves to space channel member 76 forwardly of plate 66. Channel member76 is provided with a web 82 and a pair of inturned flanges 84 (FIG.extending from the opposite sides of web 82 in a direction normalthereto and towards head 36.

Stud end 48 of rod 44 projects axially beyond channel member 76 andsupports a centering pin 86 having an axial recess 88 for engagementwith stud end 48 of rod 44. The other end of centering pin 86 terminatesin a point 90 adapted to engage the axis of a wheel hub H for centeringmeasuring head 36 relative to the wheel to be measured.

As shown in FIGS. 5, 6, and 7, web 82 is provided with longitudinallyspaced, elongated slots 92 for adjustably receiving a pair of sensors orprobes 94. One end of each probe 94 is provided with a flat head 96engagable with the rim of the wheel hub H, the other end of probe 94being threaded as shown at 98 in FIG. 7. A disc-like knob 100 is fixedlysecured to probe 94 for facilitating rotation thereof in order to effectcertain adjustments, hereinafter described. A flat-sided nut 102,disposed within the channel formed by flanges 84, is threaded onto thedistal end of probe 94 for securing the latter in a selected positionalong slot 92 in channel member 76.

Prior to the utilization of the measuring apparatus of this invention,the tires should be checked for proper inflation and the efficiency ofthe vehicles shock absorbers should be checked. Also, any play in therear wheel axle holders and the steering mechanisms should be registeredand the rim of each wheel hub should be perfectly round or concentric.After these checks are made, the operator can then advance the vehicletoward the alignment measuring apparatus 10 which is positioned on a.level surface, with wheels W oriented straight ahead, the vehicle beinghalted by the hand brake.

Referring now to FIGS. 1-4 of the drawings, apparatus 10 is adjusted ina preliminary way with arms 26 moved relative to tubular member 14 toaccommodate the spacing between wheels W. Arms 24 are inclined upwardlyto bring heads 36 to approximately the level of and near the axes of thefront wheels W. At each side of the vehicle, the centering pin 86 ismounted on the projecting stud 48 of rod 44 and aligned with the axis ofwheel hub H. Set screws 32 and 37 are then tightened to secure arm 24and measuring 'head 36 in the proper aligned orientation. The knobs 100adjacent the opposite ends of each channel member 76 are loosened inorder to position probes 94 at a spaced-apart distance corresponding tothe diameter of the rim of hub H and equidistant from centering pin 86.Probes 94 are then fixed at these selected positions by rotating knobs100 to tightly secure the threaded portions 98 of probes 94 in nuts 102with knobs 100 bearing against the outer surfaces of channel member 76.It should be noted that this adjustment can be effected by hand withoutthe use of any tools since the flat-sided nuts 102 are fixed againstrotation by flanges 84 of member 76. The effective lengths of the twoprobes 94 measured from web 82 of channel member 76 are equal.

After probes 94 are properly fixed at the correct spacing from eachother, set screw 37 is loosened and head 36 is pulled away from thewheel W and centering pin 86 is removed. In order to determine thecamber of the wheel, i.e., the vertical inclination thereof relative toa true vertical plane, head 36 is rotated within sleeve 34 to positionmeasuring channel 76 in a vertically extending position. Head 36 is thenslid toward the vehicle wheel W until the heads 96 of probes 94 engagethe rim -of the wheel hub H at diametrically opposed, vertically alignedpoints. It should be understood that the orientation of the wheels aredesigned or intended to be normally inclined slightly relative to a truevertical reference plane whereby the tops of the wheels W are disposedoutwardly of such reference plane and the bottoms of wheel W aredisposed inwardly of such plane.

Thus, when head 36 is moved inwardly toward the wheel hub H, the topprobe 94 will normally engage the hub rim before the bottom probe 94,causing channel member 76 to tilt or swing in a vertical plane about apivot defined by the side. of key 72 and the side wall edge definingopening in plate 66 as shown at X in FIG. 9. Should channel member 76swing in the opposite direction, the opposite side of key 72 and theopposite side wall defining opening 70 would serve as a pivot. When bothprobes 94 contact the hub rim, channel member 76 will be disposed in aninclined plane corresponding to the inclination of the wheel W relativeto a true vertical plane. Rod 44 is tilted along with channel member 76against the bias of spring 58 and relative to the axis of head 36causing pointer 52 to move longitudinally in slot 62 to indicate theextent of camber or vertical inclination of the measured wheel Wrelative to a true vertical plane.

Scale 64 (FIG. 5) can be calibrated in millimeters indicating thedeviation from a base at zero, or in degrees to determine the angle ofvertical inclination relative to a true vertical plane, as desired. Inany event, the movement of rod pointer 52 corresponds to the extent ofswinging movement of channel member 76 to determine the camber of wheelsW. This reading can be compared to the desired camber of the wheels,including tolerances, set forth in the reference manual for the specificvehiclebeing checked to determine whether any adjustments are necess ryfor proper wheel alignment.

In a similar manner, the toe characteristics, namely toe-in(convergence) or toe-out (divergence) of the vehicle wheels W can bemeasured. By way of example, toe-in for a pair of laterally spacedwheels means that the distance between the wheel planes of rotation atpoints on the horizontal'diameters behind the wheel axes is greater thanthe-distance between the planes at points on the same diameters in frontof the wheel axes. In order to determine the toe characteristics of thewheels W, channel member 76 is oriented in a horizontal directionparallel to the floor surface prior to advancing probes 94 against therims of the wheel hub H. Of course, slot 92 will also be oriented in ahorizontal direction and rod pointer 52 will swing in a lateraldirection along with channel member 76 a distance commensurate with theextent of convergence or divergence of wheels W relativeto a verticalplane, or reference plane, cut through the longitudinal axis of thevehide. The rear wheels are measured in the same manner as the frontwheels, as described above, except that tubular member 14 will belocated rearwardly of the vehicle behind the rear wheels.

From the foregoing, it is apparent that the objects of this inventionhave been fully accomplished. As a result of this invention, an improvedwheel alignment measuring apparatus is provided for determining bothvehicle wheel camber and toe characteristics with optimum precision.While the measuring apparatus of this invention is relatively simple inconstruction, it is durable in use and can be used by persons possessingrelatively little skill. Moreover, the relatively low cost thereofrenders it practical for use in small garages and service stations.

One form of this invention having been disclosed in detail, it is to beunderstood that this has'been done by 1 way of illustration only.

I claim:

1. A wheel alignment measuring apparatus comprising: a frame; at leastone wheel alignment measuring head; means supporting said head on saidframe for movement relative to said frame towards and away from avehicle wheel hub; an elongated member extending in a directiongenerally normal to the axis of said head; means mounting said elongatedmember on said head for pivotal movement relative thereto; means on saidelongated member engagable with diametrically opposed portions of therim of said hub for effecting swinging movement of said elongated memberinto an inclined position corresponding to the inclination of said wheelrelative to a reference plane; said measuring head comprising a tubularbody having a front end wall provided with an opening and a rear end caphaving a slot therein; said end cap having a calibrated scale formed onthe outer face thereof adjacent said slot; an elongated rod extendingaxially through said body; means biasing said rod centrally of said bodyalong the longitudinal axis thereof; said rod having one end pro- 6jecting axially through said opening and rigidly secured to saidelongated member; the other end of said rod forming a pointer movable insaid slot.

2. A wheel alignment measuring apparatus according to claim 1 whereinsaid frame includes an elongated tubular member supported at itsopposite ends on a pair of floor engaging crossbars.

3. A wheel alignment measuring apparatus according to claim 2 whereinsaid supporting means comprises an arm mounted at one end thereof onsaid tubular member for sliding movement relative thereto; the other endof said arm having'a sleeve for slidably receiving said head therein.

4. A wheel alignment measuring apparatus according to claim 1 whereinsaid rim engagable means comprises a pair of longitudinally spacedprobes of equal effective lengths mounted on said elongated member andextending in a direction normal thereto; and means adjustably spacingsaid probes apart a distance corresponding to the diameter of the rim ofthe wheel to be measured.

5. A wheel alignment measuring apparatus according to claim 1 includingmeans removably mounted on said one end of said rod for centering saidhead relative to the axis of said wheel hub.

6. A wheel alignment measuring apparatus according to claim 5 whereinsaid rim engagable means comprise a pair of longitudinally spaced probesmounted on said elongated member and extending in a direction normalthereto; and means adjustably spacing said probes apart a distancecorresponding to the diameter of the rim of the wheel to be measured.

7. A wheel alignment measuring apparatus comprising a pair of wheelalignment measuring heads according to claim 1 slidably mounted on'saidframe for adjustment toward and away from each other corresponding tothe lateral spacing of a pair of vehicle wheels.

A cup-shaped member 54 (FIGS. 7 and 9) having an opening 56 in the endwall thereof is mounted on portion 46 of rod 44 for receiving one end ofa helical compression spring 58 disposed about the forward end of rod 44and captively heldin tubular head 36 betweenthe end wall of cup-shapedmember 54 and the inner face of front end wall 40. Member 54 is securedin place on the threaded portion 46 of rod 44 by a pair of lock nuts 59bearing against the inner and outer faces of the cup member end wall.Spring 58 biases rod 44 centrally of head 36 to a position extendinghorizontally along the axis of head 36.

3, 793, 736 February 26, 1974 Patent No. Dated Inventor-(s) FrancoCufrini It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

1 Column 6, lines 39-50 should instead appear in column 2 between lines'64 and 65.

Signed and sealed this 15th day of October 1974.-

(SEAL) Attest:

McCOY M. GIBSON JR. C. NARSHALL DANN Attesting Office-r Commissioner ofPatents FORM PO-1050 (10-69) USCOMWDC 603764,

* u.s eovznuusm' PRINTING omc: 1 I969 o-aea-au.

1. A wheel alignment measuring apparatus comprising: a frame; at leastone wheel alignment measuring head; means supporting said head on saidframe for movement relative to said frame towards and away from avehicle wheel hub; an elongated member extending in a directiongenerally normal to the axis of said head; means mounting said elongatedmember on said head for pivotal movement relative thereto; means on saidelongated member engagable with diametrically opposed portions of therim of said hub for effecting swinging movement of said elongated memberinto an inclined position corresponding to the inclination of said wheelrelative to a reference plane; said measuring head comprising a tubularbody having a front end wall provided with an opening and a rear end caphaving a slot therein; said end cap having a calibrated scale formed onthe outer face thereof adjacent said slot; an elongated rod extendingaxially through said body; means biasing said rod centrally of said bodyalong the longitudinal axis thereof; said rod having one end projectingaxially through said opening and rigidly secured to said elongatedmember; the other end of said rod forming a pointer movable in saidslot.
 2. A wheel alignment measuring apparatus according to claim 1wherein said frame includes an elongated tubular member supported at itsopposite ends on a pair of floor engaging crossbars.
 3. A wheelalignment measuring apparatus according to claim 2 wherein saidsupporting means comprises an arm mounted at one end thereof on saidtubular member for sliding movement relative thereto; the other end ofsaid arm having a sleeve for slidably receiving said head therein.
 4. Awheel alignment measuring apparatus according to claim 1 wherein saidrim engagable means comprises a pair of longitudinally spaced probes ofequal effective lengths mounted on said elongated member and extendingin a direction normal thereto; and means adjustably spacing said probesapart a distance corresponding to the diameter of the rim of the wheelto be measured.
 5. A wheel alignment measuring apparatus according toclaim 1 including means removably mounted on said one end of said rodfor centering said head relative to the axis of said wheel hub.
 6. Awheel alignment measuring apparatus according to claim 5 wherein saidrim engagable means comprise a pair of longitudinally spaced probesmounted on said elongated member and extending in a direction normalthereto; and means adjustably spacing said probes apart a distancecorresponding to the diameter of the rim of the wheel to be measured. 7.A wheel alignment measuring apparatus comprising a pair of wheelalignment measuring heads according to claim 1 slidably mounted on saidframe for adjustment toward and away from each other corresponding tothe lateral spacing of a pair of vehicle wheels. A cup-shaped member 54(FIGS. 7 and 9) having an opening 56 in the end wall thereof is mountedon portion 46 of rod 44 for receiving one end of a helical compressionspring 58 disposed about the forward end of rod 44 and captively held intubular head 36 between the end wall of cup-shaped member 54 and theinner face of front end wall
 40. Member 54 is secured in place on thethreaded portion 46 of rod 44 by a pair of lock nuts 59 bearing againstthe inner and outer faces of the cup member end wall. Spring 58 biasesrod 44 centrally of head 36 to a position extending horizontally alongthe axis of head 36.